Multithreaded File/Folder Finder

using System;
using System.Management;
using System.Security.Principal;
using System.Text;
using System.Threading;
using System.Windows.Forms;

namespace FileFind
{
    /// <summary>
    /// Displays the About information for the File Find application
    /// </summary>
    public partial class About : Form
    {
        public About()
        { InitializeComponent(); }

        /// <summary>
        /// Appends the word(s) in str to the StringBuilder
        /// Each new set of str is separated from the prior set by a comma
        /// </summary>
        /// <param name="sb">StringBuilder output field</param>
        /// <param name="str">String to be appended to the sb field</param>
        private void AddRole(ref StringBuilder sb, string str)
        {   //creates a string of words separated by commas
            if (sb.Length > 1)
                sb.Append(", " + str);
            else
                sb.Append(str);
        }

        private void About_Load(object sender, EventArgs e)
        {
            ConfigInfo configInfo = new ConfigInfo();
            this.Font = configInfo.UseFont;
            this.Text = "About " + configInfo.ProductName;
            productInfoLabel.Text =
                configInfo.ProductName 
                + " - Version " + configInfo.ProductVersion
                + "  " + configInfo.ProductDate;

            AppDomain.CurrentDomain.SetPrincipalPolicy(PrincipalPolicy.WindowsPrincipal);
            WindowsPrincipal principal = (WindowsPrincipal)Thread.CurrentPrincipal;
            WindowsIdentity identity = (WindowsIdentity)principal.Identity;
            StringBuilder sysrole = new StringBuilder();
            sysrole.Append("(");
            if (principal.IsInRole(WindowsBuiltInRole.AccountOperator))
                AddRole(ref sysrole, "account operator");
            if (principal.IsInRole(WindowsBuiltInRole.Administrator))
                AddRole(ref sysrole, "administrator");
            if (principal.IsInRole(WindowsBuiltInRole.BackupOperator))
                AddRole(ref sysrole, "backup operator");
            if (principal.IsInRole(WindowsBuiltInRole.Guest))
                AddRole(ref sysrole, "guest");
            if (principal.IsInRole(WindowsBuiltInRole.PowerUser))
                AddRole(ref sysrole, "power user");
            if (principal.IsInRole(WindowsBuiltInRole.PrintOperator))
                AddRole(ref sysrole, "print operator");
            if (principal.IsInRole(WindowsBuiltInRole.Replicator))
                AddRole(ref sysrole, "replicator");
            if (principal.IsInRole(WindowsBuiltInRole.SystemOperator))
                AddRole(ref sysrole, "system operator");
            if (principal.IsInRole(WindowsBuiltInRole.User))
                AddRole(ref sysrole, "user");
            sysrole.Append(")");
            useridLabel.Text = "User: " + Environment.UserName + " " + sysrole;

            machineName.Text = "Machine name: " + Environment.MachineName;

            OSVersionLabel.Text = Environment.OSVersion.ToString();

            CLRVersionLabel.Text = "CLR Version " + Environment.Version.ToString();

            processorInfoLabel.Text = Environment.GetEnvironmentVariable("processor_identifier");

            string[] logical_drives = Environment.GetLogicalDrives();
            processorIdLabel.Text = "System has " + Environment.ProcessorCount + " processors and "
             + logical_drives.Length.ToString() + " logical disks";

            string str = null;
            ManagementObjectSearcher objCS = new ManagementObjectSearcher("SELECT * FROM Win32_ComputerSystem");
            foreach (ManagementObject objMgmt in objCS.Get())
            { str = objMgmt["totalphysicalmemory"].ToString(); }
            long physmem = Convert.ToInt64(str);
            systemRAMLabel.Text = "Physical memory " + physmem.ToString("N0") + " bytes";
        }
    }
}